Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
vai cuu » vai cua
dan vai » dan va, dan tai, dan vat
van cam » van nam, van lam, van cau
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va
va dan » ca dan, va dao, va dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ((ky lang) or (ky dang)) xa hoi. hieu van cam xuc va dan vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((ky lang) OR (ky dang)) xa hoi. hieu van cam xuc va dan vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ((ky lang) or (ky dang)) xa hoi. hieu van cam xuc va dan vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ((ky lang) or (ky dang)) xa hoi. hieu van cam xuc va dan vai cuu tre*.